1. Field of the Invention
The present invention relates generally to aircraft seat structures and more specifically to aircraft seat structures used in conjunction with airbag restraint systems.
2. Description of Related Art
Passenger safety systems heretofore found in vehicles such as automobiles and aircraft have been of two principal types, specifically, seat belts and airbags. Possibly the earliest to be used was the passenger lap belt which was attached to fixed sub-structure at each end and was joined over the users lap by suitable buckling devices. Normally one of the two pieces making up the belt was of fixed length while the length of the other piece could be adjusted in order that the belt could accommodate users of all sizes. This type of belt was used for many years in automobiles and remains to this day the principal type of safety restraint used for passenger restraint in private and commercial aircraft.
To further protect against possible injury, the lap-belts in automobiles were modified to include a shoulder strap that was attached at a third fixed point to restrain the passenger""s upper torso against forward movement in a crash event. More recently, in the case of passenger automobiles, passive restraints, or airbags, have been utilized to protect against injury in the event of a crash. These bags, which are inflated by compressed air or other gases, are mounted in the automobile steering column and in other fixed locations within the automobile, such as the dash board and side panels. In the event of sudden deceleration of the automobile, as in a crash, sensors identify the event and the compressed air or other gas are released to expand the bags at high speeds directly toward the passengers to prevent their forward movement. Airbags have proven generally effective in providing passenger protection, especially when used in conjunction with safety belt restraints.
Even more recent has been the idea of utilizing passive restraints, or airbags, in aircrafts to protect passengers in e event of a crash. Such passive restraints are disclosed in U.S. Pat. No. 5,984,350, which is assigned to the same Assignee as the present application, and the disclosure of which is incorporated herein by reference. The aircraft passive restraint includes a safety belt that includes first and second lengths that are each fixed at one end to the aircraft seat structure and are connectable one to the other at the other end at a location over a user""s lap. The fixed portion of the belt contains: (i) a deployable airbag; (ii) a torsion element which positions or orients the belt so that the bag is deployed away from the user; (iii) a gas conducting tube that directs gas from a gas source to the gas bag; and (iv) an outer, protective cover assembly that is rupturable at least in the area adjacent to the gas bag to permit its expansion.
The system further includes a source of gas, control and firing circuitry including electronics for identifying a crash event. The power source of the system can be either: (a) a dedicated source of battery supplied electricity which is independent of the vehicle electrical power source; or (b) a dedicated vehicle power source. A switch mechanism is included in the belt buckle and in the belt tang that permits system activation when the two belt lengths are oriented correctly and joined with the airbag positioned for expansion away from the users body.
In previous uses of passive restraint systems in aircraft, a separate compartment under the seat structure was required to house the source of gas. This additional compartment added weight to the aircraft and eliminated space below the seat normally used for passenger storage of luggage.
In the present invention, a passive restraint system in an aircraft utilizes the seat structure of the aircraft to store the source of pressurized gas or solid fuel necessary to expand the passive restraint. The seat structure of the aircraft comprises multiple hollow tubes, and these hollow tubes can be utilized to either store pressurized gas or solid fuel directly, or to house a pressurized gas vessel that stores pressurized gas or solid fuel. Thus, no additional aircraft seat space, beyond the already existing seat structure, is required to house a pressurized gas vessel. By using the existing seat structure to house the source of pressurized gas or solid fuel, significant space and weight savings can be realized, both of which are important factors in aircraft seat design.
Current aircraft seat tubes can be used in accordance with the present invention to house a pressurized gas vessel, or the aircraft seat tube can be modified to store the pressurized gas by incorporating different diameter tubes, tube wall thickness, tube material, and tube manufacturing methods depending on the pressures required in the source of pressurized gas. The ignition device and gas exit port used in the passive restraint system can be made integral to the seat tube through the placement of a header section that holds the ignition device, gas pressure release membrane, gas flow control device, gas exit port, and connection to gas conducting tube.
These and other features and advantages of the invention will be apparent upon consideration of the following detailed description of the presently preferred embodiments of the invention, taken in conjunction with the claims and appended drawings, as well as will be learned through the practice of the invention.